The relationship between functional abnormalities and structural changes in disease has
been the focal point of pathological investigation since the eighteenth century. However, the
simultaneous study of these two complementary facets in human disease required proper
methods, now available in the excellent and discriminating renal function tests and the
percutaneous renal biopsy. Although the functional tests have provided numerical data for
analysis, the standard disease descriptions and classifications have not provided an assay …